Many Mac users have reported an enigmatic error which comes out of the blue. It can come using apps on Mac, after logging in or logging out etc. The error message says “Unapproved caller, SecurityAgent may only be invoked by Apple software”. It is but natural to freak out on this error message because it talks about some secure agent, unapproved caller—a clear indication that this has to do with the security of your system. But you can fix Unapproved caller. SecurityAgent may only be invoked by Apple software error in Mac without worrying about anything as it is a common error.
The error comes when the processes and cache in your Mac collide i.e. the system scheduler gets confused and thinks that the system calls nad RPC are coming from unapproved places.
The best way to fix Unapproved caller. SecurityAgent may only be invoked by Apple software is to run your Mac in the Safe mode.
Once you boot your system in Safe mode and then boot it in the normal mode, this error will fade away as the system will get time to fix things and maintain the order.